Add functions to help debug object leaks
Added gdb rph to print object given its subtend handle.
A slew of GC fixes
* When we fill up the young object space, we spill right away to the
mature space and set a flag that we need to collect the young space.
* GC is only done currently when a task completes
Added gdb rps for simple show. Fixups for TypeInfo::show helpers.
Remove STATE argument from debug functions
use 'rbt' to get a ruby backtrace, and 'rp' to have the VM show an
Cleanup stack usage and fix interpreter
Remove Task->stack, added Task methods for manipulating the stack that
VMMethod contains a resume now, so that the bytecode can again be
interpreted. Currently, this is the default while LLVM continues to be